NEAR SURFACE STORAGE OF THERMAL ENERGY

Energy management presents unique challenges for heating and cooling of buildings and other infrastructure systems. This can be particularly important in applications where seasonal energy demand is heating dominant, either be as a result of regional climate (i.e. colder regions) or due to the application specific heating demand (i.e. bridge deck deicing). Integrated technologies which can capture and store heat can be critical for energy efficient and sustainable systems. Ground can be utilized as a storage medium for the heat energy collected in the summer to be extracted in the winter when needed. Ground storage of heat allows the better management of heat over seasons as well as its distribution among the built environment with different energy demand profiles. Heat energy can be collected in the summer through circulation tubes embedded in the asphalt pavement and/or structural panel components. The collected heat energy can be injected into the ground through the geothermal loop system, which can be extracted from the ground and used for heating as necessary. For example bridge decks can benefit from the extraction of stored heat from the ground to prevent icing in the winter. Similarly ground-source heating can be used for other purposes such as drying of grains at agricultural storage facilities. This study focuses on the concept of thermal harvesting and investigates the challenges of seasonal ground storage systems. Analyses have been performed where heat injection is simulated over the summer using a thermal pile. Heat is extracted during the winter and the ground temperatures are monitored. The analyses considered several injection rates and pile configurations. The results provide insight on the sustainable operation of seasonal ground storage systems.